Piston ring



Feb; 211527;

E. F. DICKIESON, JR

PISTON RING Filed June 13, 1922 INVENTOR 66 M m ,e ATT RNEYs Y. \A\\ \MVAM 6. w

Patented Feb. 22, 1927. v

UNITED STATES EDWARD F. DICKIESON, JR.,

OF BROOKLYN, NEW YORK.

PISTON RING.

Application filed June 18,

This invention relates to pistons and piston rings cooperating therewith to seal the expansion chamber of an engine, the invention being particularly adapted though not necessarily limited to use in internal combustion engines. I

Since the introduction and rapid development of internal combustion, and particularly automotive engines, many attempts have been made to provide a satisfactory cylinder packing. From the earliest ring consisting simply of .a split concentric band, the art has advanced to the eccentric or uniform pressure type and has included two. and three-part rings of differing construction and more or less satisfactory performance. Generally the rings have been designed to operatein parallel-walled grooves in the piston and have been subject to breakage when slightly worn because of lateral movementwhich permitted jamming in the .grooves.

Inattempting to overcome the undesirable features of piston rings as heretofore known, it is necessary to consider the conditions un-' der which the ring operates. The piston attainsa temperature of aboutBOfi? F. higher than the cylinder wall while the rings operate at an intermediate temperature so, thatthe expansion of the severalparts is unequal. This condition is aggravated with aluminum pistons which are coming into general use ecause of certain advantages which they present. Furthermore, the bore of the cylin der is never exactly true. To compensate for the variations due to different temperatures and coefficients of expansion and inaccuracies in machining, it is necesary to employ rings, and if the expansion chamber is to e successfully sealed, the rings must be capable of radial expansion and contraction. To prevent jamming and breaking the rings must be supported by the walls of the groove as they expand and contract, and

the su port must be effective even after considera le wear has occurred.

It is the object of this invention to provide a piston ring which avoids thedifiiculties heretofore experienced and which ensures a tight combustion chamber under all conditions of piston speed and temperature even after the rings havev become worn because of unavoidable friction which, however, is reduced to a minimum by the construction hereinafter described.

Further ob ects and advantages of the in:

1922. Serial No. 567,946.

vention will be apparent as it is better understood by reference to the following specification and accompanying drawing, in which Fig. 1 is a view in perspective of a piston ring embodying the invention; and

Fig. 2 is an enlarged cross-sectional view of aportion of a cylinder wall, piston and cooperating ring.

My invention depends upon the use of split packing and wedging rings, both preferably of the uniform pressure type and cooperating with the walls of a groove of special form to properly balance and distribute which'is the most frequent source of breakage in piston rings. The preferred angular relation of the bearing surfaces on the groove wall, wedging and packmg rlngs Wlll der pressure and piston speed under which the ring is required to operate. In general an included angle'of from 50 to between the bearing face of the packing ring and the wall of the groove is most satisfactory, The wedge wlll, of course, have a corresponding 'angularity so that it, will closely fill the space between the packing ring and the wall of the groove and follow the packing ring as the latter expands or contracts.

vary with the particular conditions of cy'lin- Referring to the drawing, 5 indicates the a cylinder wall and 6 the piston which may be of any'of the usual types, dltl'erlng therefrom only in the provision of a groove or grooves 7 having one lateral wall 8 in a plane perpendicular to the axis of the cyl1nder, and the other lateral wall 9 angularly.

disposed with respect to that plane. In other words, the groove is wlder at the bottom than at the'top and may be designated.

as an undercut groove for-convenience of expression. A packing ring 10 is provided with a cylindrical face 11 for engagement with the cylinder wall and a plane face 12 which is tightly pr'essed'against-the Wall 8 llU of the groove to prevent the entrance of gas into the roove. Another face 13 of the packing ring bears an angular relation to the plane of the wall 8. A wedging ring 14 of wedge-shaped cross-section, having opposite an ularly-disposed faces 15 and 16, is dispose between the face 13 of the packing rin and the wall 9 of the groove. The included angle between the faces 15 and 16 is preferably about 53, although this angle may vary under differing conditions and reference thereto is merely illustrative. A space is provided below the packing ring for the collection of oil, and one or more ducts 17 are preferably provided to drain this oil into the interior of the piston. These ducts are not, however, essential to the invention.

As will be readily understood, when the rims are compressed in the groove they tend to expand and thus the wedging ring holds the packing ring in close engagement; with both the cylinder wall and the perpendicular wall of the groove, the pressure exerted by the wedglng ring being divided into two-components and acting on both of the walls mentioned. If the packing ring is caused to contract by any irregularit in the,

cylinder wall, the wedging ring a 0 contracts but holds the packing ring nevertheless in true alignment, thus preventing 'amming and leakage of gas. As the pac ing ring wears, the wedging ring automatically takes up the wear and maintains the relations described until the packing rin has been worn to such a point that it will not expand further.

Among the advantages of my invention which distinguish it from piston rings heretofore in use are the eflective sealing of the combustion chamber both at the cylinder wall and groove contact surfaces, the wedging action of the wcdging ring which ensures this condition when the packing ring is expanded or contracted and the freedom from vibration and consequent possibility of jamming and breaking the ring. These and other advantages are of particular importance in connection with aluminum pistons parts without departing from the invention or sacrificing any of the advantages thereof.

I claim 1. In a cylinder packing the combination of a piston having an inwardly diverging groove, the upper-wall of which overhangs the lower wall, said lower wall being angu larly disposed with reference to a plane perpendicular to the axis of the piston, and a twopart expanding ring, one of the parts being wholly within the groove and having a face cooperating with said angularly disposed wall and another face angularly disposed with reference to said erpendicular plane and cooperatingwith tile other part of the ring to expand it outwardly.

2. A piston having a circumferentially extending packing groove, the upper side of said roove being perpendicular to the axis of the piston, the lower side being beveled downwardly and inwardly and the outer ed e of said lower side extending downwar ly and outwardly.

3. In a cylinder packing, the combination of a piston having a circumferentially extending packing groove, the upper side of said groove being perpendicular to the axis of the piston, and its lower side being beveled downwardly and inwardly, and the outer edge of the lower side of said groove extending downwardly and outwardly, and a two part piston ring in said groove comprising a packing part having a cylindrical surface, a surface perpendicular thereto, and

a surface obliquely disposed with relation to the cylindrical surface, and a wedging part having two surfaces at an acute angle, one of which cooperates with the obliquely disposed surface of the packing part, and the other of which cooperates wlth the beveled lower wall of the groove.

In testimony whereo I aflix my signature.

EDWARD r. DICKIESON, JR. 

